In contrast, sarcoma-iPSC mice that were not given Dox were vigorous and did not develop any CCS-like sarcomas even at 6 months of age (n = 7), except for one mouse that developed EWS/ATF1-independent rhabdomyosarcoma (Supplementary Fig. 2e, f). Here, EWSR1 is linked to rhabdomyosarcoma.